When engine radiators become clogged with debris, the radiator becomes inoperative or, partly so, to the extent that the engine overheats. In the past, stationary mesh screens have been used in advance of the radiator when an engine is being used to power a machine at a worksite in which "dirty air" might create problems, but these screens have tended to clog and require frequent cleaning, particularly in operations in which entraining matter is created at the worksite.
Other attempts to solve the problem have involved the use of spinning perforated or mesh cylinders to admit air to radiators of the type which typically are used on agricultural machinery. These, also, tend to become easily clogged and to require frequent and difficult manual cleaning of the cylinders and radiator.